The present invention relates to a silver brazing alloy and to a method of brazing metal parts.
It is known to torch braze, induction braze, furnace braze, or vacuum braze metal parts, such as steel parts, using non-ferrous brazing alloys, also known as filler metals. Typical filler metals include silver, gold, nickel, and copper brazing alloys. Silver brazing alloys are more costly and, in general, melt at lower temperatures than copper alloys.
One silver brazing alloy which has been used in the prior art is an alloy containing 56 wt % silver, 42 wt % copper, and 2.0 wt % nickel. Despite the wide spread use of this silver brazing alloy, there remains a need for an alloy which has improved brazing characteristics, particularly wettability.
Accordingly, it is an object of the present invention to provide a silver braze alloy having improved wettability.
It is a further object of the present invention to provide an improved brazing method which does not require nickel plating of a stainless steel substrate prior to brazing.
The foregoing objects are attained by the silver braze alloy and the brazing method of the present invention.
In accordance with the present invention, a silver braze alloy consists essentially of from about 52.25 wt % to about 57.0 wt % silver, from about 38.95 wt % to about 43.0 wt % copper, from about 0.5 wt % to about 5.5 wt %, preferably from about 1.0 wt % to about 5.5 wt %, manganese and up to about 2.5 wt %, preferably from about 1.5 wt % to about 2.5 wt % nickel.
A method for brazing a part in accordance with the present invention broadly comprises providing an article formed from a ferrous material, applying a brazing-material to the article formed from an alloy consisting essentially of from about 52.25 wt % to about 57.0 wt % silver, from about 38.95 wt % to about 43.0 wt % copper, from about 0.5 wt % to about 5.5 wt % manganese, and up to about 2.5 wt % nickel, and heating the article and the brazing material at a temperature in the range of from about 900xc2x0 C. to about 1050xc2x0 C. for a time period sufficient to melt the brazing material.
Other details of the silver braze alloy and the method of the present invention, as well as other objects and advantages attendant thereto, are set forth in the following detailed description and the accompanying drawing.